Injection pump
Fuel pump
Fuel pump
2020-06-03
Hand brake valve
2020-06-02

Injection pump

Injection pump Introduction

Injection Pump is the device that pumps diesel (as the fuel) into the cylinders of a diesel engine. Traditionally, the injection pump was driven indirectly from the crankshaft by gears, chains or a toothed belt (often the timing belt) that also drives the camshaft. It rotates at half crankshaft speed in a conventional four-stroke diesel engine. Its timing is such that the fuel is injected only very slightly before top dead centre of that cylinder's compression stroke. It is also common for the pump belt on gasoline engines to be driven directly from the camshaft. In some systems injection pressures can be as high as 620 bar (8992 psi)

The fuel injection pump performs four functions:

  • Producing the high fuel pressure required for injection
  • Metering the exact amount of fuel for each injection cycle
  • Distributing the high-pressure, metered fuel to each cylinder at the precise time
  • Varying the timing relative to engine speed.
A cam ring with three plungers, a rotor, and an electronically controlled fueling solenoid valve is used to develop and distribute the high pressure required for injection. A worn or damaged internal transfer pump, plunger, or fueling valve can affect the pressure and amount of fuel injected, thus reducing the power from the engine. Generally, if the fuel injection pump is injecting fuel from one outlet, it will deliver from all outlets.
Timing Principles Timing in the is controlled by an internal timing piston coupled to a cam ring inside the pump. The timing piston is moved by fuel pressure. The amount of fuel pressure in the timing piston assembly housing is controlled by an internal transfer pump and a pulsating timing solenoid valve. As pump speed increases, the fuel pressure to the timing piston assembly also increases. Based on the inputs from the fuel pump control module (FPCM), the timing solenoid valve pulses to vary the pressure to move the timing piston, which results in the cam ring moving to the desired position to achieve the commanded timing.
The more pressure created by the internal transfer pump and timing solenoid valve, the more the timing will advance; therefore, timing range capability is increased at higher rpm's.

Injection pump Picture

Features and Benefits:

  • Latest hardware upgrades for improved performance and reliability
  • Remanufactured OEM diesel injection pump
  • Affordable alternative to a new OEM pump
  • 2-Year Unlimited Mileage warranty

New types

Mechanical pumps are gradually being phased out in order to comply with international emissions directives, and to increase performance and economy. From the 1990s an intermediate stage between full electronic control were pumps that used electronic control units to control some of the functions of the rotary pump but were still mechanically timed and powered by the engine.
The first generation four and five cylinder VW/Audi TDI engines pioneered these pumps before switching to Unit Injectors. These pumps were used to provide better injection control and refinement for car diesel engines as they changed from indirect injection to much more efficient but inherently less refined direct injection engines in the 1990s.
The ECUs could even vary the damping of hydraulic engine mounts to aid refinement. BOSCH VP30 VP37 VP44 are example pumps. Since then there has been a widespread change to common rail diesel systems and electronic unit direct injection systems. These allow for higher pressures to be developed, and for much finer control of injection volumes, and multiple injection stages compared to mechanical systems.
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